C is correct answer.
On C its saids, no irrational number is rational it's statements is false.
Hope it helped you.
-Charlie
Answer:

Step-by-step explanation:
The area of trapezoid is given by the formula:

Where
A is the area
b_1 is base 1
b_2 is base 2, and
h is the height
Looking at the figure, base 1 is the left line which goes from y = 3 to y = 3, so 6 units. Also, base 2 is the right line which goes from y = -3 to y =5, so 8 units.
The height is the horizontal distance in the middle, which goes from x = -2 to x = 3, so 5 units. Hence area of trapezoid is:

Now, area of semicircle is:

Where
A is the area
r is the radius
Looking at the figure, the diameter (twice radius) goes from y = -3 to y = 3, so 6 units. But radius is half of that, so 3 units. Hence area of semicircle is:

Total area of the figure is 
Total volume of water=12*10*11
Let final height of water be h
Total volume of water=h*(12*10+7*10+6*5)
I'm really not good at this .. but if u want multiply or dived the cm's .. math is not my best subject if I'm wrong .. sorry
It's pretty simple! So it looks like you are learning proportions. You would cross multiply to achieve your answer.
First, let's do your first problem:
2 12
--- = ----
5 n
You would take 5 and multiply it by 12 and get 60! Then you would do the same with 2 times n, giving you 2n (because you do not know what n represents YET.)
Now you should have this:
60=2n OR 2n=60
We must isolate our variable, in order to do that, get rid of two! But how? You would do this by dividing 2n by 2. Yet in equations, when you do something to one side, you must do it to the other because they must be EQUAL! (hence the "equa-" in equation)
2n=60
--- ---
2 2 DIVIDE 2 into 60
----------
n= 30 Simplify!
Your final answer for the first question is n= 30!